Fuel cell stacks are devices for generating an electromotive force from power generators by supplying hydrogen as a fuel gas and oxygen (air) thereto. In general, a fuel cell stack has a structure that an electrolyte film (proton conductive film) of each fuel cell is held between gas electrodes and is operable to obtain a desired electromotive force. Such fuel cell stacks have been greatly expected as applicable to electric cars and hybrid type vehicles and actually developed toward the practical use. In addition to these applications, fuel cell stacks are being studied to be usable in new applications quite different therefrom, for example, as new power sources for portable electric equipment in place of the existing dry cells and chargeable batteries by making effective use of advantages of the fuel cell stacks in terms of easy reduction in weight and size.
By the way, in each of the above-described applications, it is required to simply, stably deliver hydrogen representative of a fuel gas to a fuel cell stack, and more specifically, it is essential to construct a so-called hydrogen delivery system.
In the case of constructing such a hydrogen delivery system, it is important to ensure an interface between a fuel gas server (hydrogen server) and a fuel cell stack. For example, in the case of constructing a hydrogen delivery system of a structure that hydrogen is delivered from a hydrogen server to power generators of a fuel cell stack via a fuel gas storing unit configured as a fuel cartridge, it is essential to acquire pieces of information on the necessary filled amount, optimum flow rate of the fuel gas, kind of a storage material used for the fuel cartridge, and the like, and it is required to suitably control the hydrogen server and the like on the basis of these pieces of information.
The hydrogen delivery system of such a type also requires the temperature control of the fuel cartridge and the like. In the case of using storage/release of a fuel gas (hydrogen gas) in/from a storage material for delivering the fuel gas, since the storage material generally becomes exothermic at the time of storage of the fuel gas and endothermic at the time of release of the fuel gas, it is desirable to control the temperature of the fuel cartridge on the basis of whether the storage material is in the exothermic state or in the endothermic state.
The present invention has been made to meet these various requirements. Accordingly, an object of the present invention is to provide a new fuel gas mediator having functions of storing, displaying, and transmitting various kinds of information. Another object of the present invention is to provide a fuel gas mediator capable of performing the temperature control thereof.